Fluid heating system

ABSTRACT

This invention relates to a fluid heating system, wherein the fluid is capable of being heated by means of solar energy, the fluid heating system including:—an outer housing;—an inner housing contained within the outer housing and including an absorbent material core located within the inner housing to define a flow passage between it and the walls of the inner housing; the absorbent material core being suitable for absorbing solar energy transmitted through the outer and inner housings; and—wherein the outer housing; inner housing; and the absorbent material core are arranged such that solar energy is transferred through the fluid in the flow passage before being absorbed by the absorbent material core.

FIELD OF THE INVENTION

This invention relates to a fluid heating system and more particularly, but not exclusively, to a solar energy system for use in heating fluid.

BACKGROUND TO THE INVENTION

Solar heating systems have long been known to be an efficient method for utilizing solar energy to heat a fluid such as water for subsequent storage or for household and industrial use. A conventional solar panel includes a blackened absorber plate having heat absorber tubes, such as copper or aluminium tubes which may be embedded therein or affixed thereto. The absorber plate is contained within an outer transparent housing to prevent heat loss in cool weather. As the solar energy radiates down on the solar water panel, the absorber plate will absorb the solar energy and transfer thermal energy to the water flowing through the absorber tubes.

Although solar heating systems provide an effective alternative to conventional sources of power, such as electricity, gas or fossil fuels, a number of disadvantages are often encountered. The absorber plate of the aforesaid conventional solar panel creates a thermal barrier between the absorber surface heated by solar energy radiating onto the absorber plate and the water that is to be heated. Conductivity through this thermal barrier causes the water flowing through the absorber tubes to heat gradually, requiring a long period of time to heat the water to the desired temperature. A further disadvantage of such solar panel heating systems is the high costs required to install such systems.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a fluid heating system which will, at least partially, alleviate some of the abovementioned disadvantages.

SUMMARY OF THE INVENTION

According to the invention there is provided a fluid heating system, wherein the fluid is capable of being heated by means of solar energy, the fluid heating system including:

-   -   an outer housing;     -   an inner housing contained within the outer housing and         including an absorbent material core located within the inner         housing to define a flow passage between it and the walls of the         inner housing;     -   the absorbent material core being suitable for absorbing solar         energy transmitted through the outer and inner housings; and         wherein the outer housing; inner housing; and the absorbent         material core are arranged such that solar energy is transferred         through the fluid in the flow passage before being absorbed by         the absorbent material core.

In a preferred form of the invention, the fluid is water, preferably potable water.

The invention further provides for the outer housing to include a reflective surface, preferably in the form of a tin foil shield, for collecting and focusing solar energy onto the absorbent material core.

There is also provided for the fluid heating system to include an actuating means for facilitating thermostatic control of the heating system, preferably in the form of a rotating means for rotating the outer housing from a first position wherein the reflective surface is exposed to solar energy to a second position wherein the reflective surface is concealed from solar energy as well as the absorber material core.

In one form of the invention, the absorbent material core may be a black, hollow, cylindrical core. In another form of the invention, the absorbent material core is a black, plastic, hollow cylindrical core. In a specific embodiment of the invention, the absorbent material core is a black, hollow, cylindrical core in the form of rubber crumb.

Preferably, there is provided for the outer housing to include a transparent plastic tubular body having an inlet at one end thereof and an outlet at an opposite end of the outer housing. The inner housing, also having an inlet and outlet, includes a transparent plastic body adapted to be contained within the outer housing such that the inlet and outlet of the inner housing are located within the inlet and outlet of the outer housing.

More preferably, there is provided for the transparent plastic tubular body of the outer housing to be constructed from a plurality of polyethylene terephthalate (PET) 2 L cold drink bottles and for the body of the inner housing to be constructed from a plurality of PET 500 ml cold drink bottles.

The number of cold drink bottles arranged to form the outer and inner housings of the fluid heating system may vary depending on the desired volume of fluid to be heated. It will be appreciated that the cool drink bottles are thus arranged to form a solar energy absorber array.

In a specific embodiment of the invention, there is provided for the body portions of the plurality of 2 L cold drink bottles, without bottlenecks and the pentaloid bases attached thereto, to be arranged end-to-end to form the tubular body of the outer housing. There is further provided for one 2 L cold drink bottle, having a bottleneck, and one 2 L cold drink bottle, having a pentaloid base, to be positioned at opposite ends of the tubular body of the outer housing to provide the inlet and outlet, respectively.

There is still further provided for the plurality of 500 ml cold drink bottles to be arranged bottleneck-to-end to form the inner housing. This arrangement allows for fluid communication through the inner housing.

A further feature of the invention provides for the fluid heating system to include a plurality of outer housings. Preferably, the plurality of outer housings is supported on a frame.

A still further feature of the invention provides for a water reservoir to be mounted above the frame.

A yet further feature of the invention provides for the water reservoir to include a cold water supply inlet located at a bottom end of the water reservoir in fluid communication with a hot water delivery outlet located at a top end of the water reservoir. The water reservoir further includes a main delivery water pipe connected at one end to the cold water supply inlet and to a first series of manifolds at its other end.

The first series of manifolds are connected to the inlets of the inner/outer housings and a second series of manifolds are connected to the outlets of the inner/outer housings. The second series of manifolds are also connected to a further water pipe that supplies water flowing through the flow passages of the inner housings to the water reservoir.

Preferably, the water reservoir is covered with an insulating material to prevent heat escaping from the water reservoir so as to maintain high water temperatures for a prolonged period of time. In a specific embodiment of the invention, the insulating material is polystyrene.

The water heating system is controlled so as to heat the fluid to a maximum temperature in the range of 50-70° C.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is described below, by way of example only, and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a fluid heating system according to the invention;

FIG. 2 is an expanded view of the inner and outer housings of FIG. 1; and

FIG. 3 is a cross-sectional view of the inner housing contained within the outer housing of FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the drawings, in which like numerals indicate like features, a fluid heating system is generally indicated by reference number 10.

With reference to FIG. 1, a fluid heating system 10 for heating fluid, such as water, by means of solar energy includes a plurality of outer housings 20, each outer housing contains an inner housing 30. The outer housing is supported on a frame 40 and a water reservoir 50 is mounted above the frame 40. The inner housing 30 includes an absorbent material core 60 located within the inner housing 30 to define a flow passage between it and the walls of the inner housing 30. The absorbent material core 60 is a rubber crumb solid core suitable for absorbing solar energy transmitted through the outer 20 and inner housings 30. Each outer housing 20, inner housing 30 and the absorbent material core 60 are arranged such that solar energy is transferred through the water in the flow passage before being absorbed by the absorbent material core 60.

As shown in FIG. 2, the transparent plastic tubular body of each outer housing 20 is formed from a plurality of polyethylene terephthalate (PET) 2 L cold drink bottles 20.1. The plurality of 2 L cold drink bottles 20.1, without bottlenecks and the pentaloid bases attached thereto, are arranged end-to-end. One 2 L cold drink bottle 20.1, having a bottleneck, and one 2 L cold drink bottle 20.1, having a pentaloid base, are positioned at opposite ends of the tubular body of each outer housing to provide an inlet 20.2 and an outlet 20.3, respectively.

FIG. 2 further shows the inner housing 30 formed from a plurality of PET 500 ml cold drink bottles 30.1 arranged bottleneck-to-end. This arrangement allows for fluid communication through the flow passage of each inner housing 30. It will be appreciated that the inlet and outlet of the inner housing are located within the inlet 20.2 and outlet 20.3 of the outer housing.

The number of cold drink bottles (20.1 and 30.1) arranged to form the outer and inner housings of the fluid heating system may vary, depending on the desired volume of water to be heated. Together they are arranged to form a solar energy absorber array.

Each outer housing 20 includes a reflective surface 70 in the form of a tin foil shield for collecting and focusing solar energy onto the absorbent material core, as shown in FIG. 3. The reflective surface covers 50% of the circumference of the outer housing 20. The reflective surface may be located either on the inner surface of the outer housing 20 or on the outer surface of the outer housing 20. It is envisaged that the reflective surface 70 of the tin foil may also be provided with an insulating member, such as polystyrene, and the polystyrene may thus be a backing to the tin foil.

As further shown in FIG. 1, the water reservoir includes a cold water supply inlet 80 located at a bottom end of the water reservoir 50 in fluid communication with a hot water delivery outlet 90 located at a top end of the water reservoir 50. A main delivery water pipe 100 is connected at one end to the cold water supply inlet and to a first series of manifolds 110 at its other end. The first series of manifolds 110 are connected to the inlets 20.2 of the inner/outer housings (30,20) and a second series of manifolds 120 are connected to the outlets 20.3 of the inner/outer housings (30,20). The second series of manifolds 120 are also connected to a further water pipe 130 that supplies water flowing through the flow passages of the inner housings 30 to the water reservoir 50. This assembly facilitates fluid communication between the flow passages of the inner housings 30 and the water reservoir 50.

The water reservoir 50 is covered with an insulating material in the form of polystyrene to prevent heat escaping from the water reservoir so as to maintain high water temperatures for a prolonged period of time.

The water reservoir further includes a plurality of PET 2 L cold drink bottles (not shown) positioned in a rectangular arrangement within the water reservoir 50, the bottles being in fluid flow communication with each other by means of a series of manifolds (not shown) connecting the bottles together.

In order to control the flow of fluid in the bottles in the water reservoir 50, connectors (not shown) are provided for connecting the bottles to the series of manifolds (not shown), wherein the diameter of the connectors for the lower most layer of bottles is smaller than the diameter of the connectors for the upper most layer of bottles.

Accordingly, and if the water reservoir 50 is mounted at an angle above the frame 40, the aforesaid diameter difference is necessary to prevent the mixing of the hot and cold water portions flowing through the bottles in the water reservoir 50 such that there is increased flow of water through the layers which have more bottles relative to the layers which have less bottles.

It is envisaged that the bottleneck and pentaloid base, forming the inlet and outlet of each outer housing, respectively, may include grooves to accommodate a gear mechanism in order to facilitate the operative rotation of the outer housings from a first position wherein the reflective surface is exposed to solar energy to a second position wherein the reflective surface as well as the absorber material core are concealed from solar energy. This rotation allows for thermostatic control of the heating system.

In use, each outer housing of the fluid heating system 10 is supported on the frame 40 and a water reservoir 50 is mounted at an angle above the frame (as shown in FIG. 1). Cold water within the water reservoir 50 flows from the water reservoir 50, through the cold water supply inlet located at the bottom of the water reservoir through the main delivery water pipe 100 and through the first series of manifolds 110 connected to the inlets 20.3 of the outer housings 20. The water then passes through the flow passages of the inner housings 30 contained within the outer housings 20.

As the sun shines on the fluid heating system, the transparency of the outer housings 20 and inner housings 30 allows solar energy to be transmitted through the water in the flow passages before being absorbed by the absorbent material core 60. The solar energy absorbed by the absorbent material core 60 is converted into thermal energy that, in turn, is absorbed by the water, thus resulting in the rapid heating of the water. Each outer housing insulates a pocket of air surrounding the inner housing 30 in order to achieve the desired increase in temperature. The outer housing 20 further creates a thermodynamic barrier so that heat loss to the atmosphere is reduced while also protecting the inner housing 30 from impact damage from the elements, for instance hail.

As the water inside the flow passage of each inner housing 30 starts to heat, this water expands slightly and becomes less dense than the cold water in the water reservoir mounted above the frame. Due to thermosyphon flow, gravity pulls the more dense, cold water down from the water reservoir 50 and through the main delivery water pipe 100. The cold water pushes the heated water through the flow passage of each inner housing 30 and into the top of the water reservoir 50, thus introducing warm water in the water reservoir 50. This process is repeated until sufficient warm water is present in the water reservoir. The water in the fluid heating system reaches a maximum temperature controlled to be in the range of 50-70° C. The heated water then flows from the water reservoir 50, through the hot water delivery outlet 90 for industrial or domestic use.

It is envisaged that the gear mechanism connected to the inlets and outlets of the outer housings facilitates rotation of the outer housings from a first position wherein the reflective surface and the absorber material core are exposed to solar energy to a second position wherein the reflective surface and the absorber material core are concealed from solar energy. This rotation allows for thermostatic control of the heating system and prevents the structural integrity of the plastic outer and inner housings from becoming distorted from excessive exposure to direct sunlight at temperatures above 65° C. wherein shrinking of the bottles takes place.

It is envisaged that the invention as described above will solve the problems associated with known technology.

The above is only one embodiment of the invention and it will be appreciated that many variants in detail are possible without departing from the spirit and scope of the invention. For example, a cover that unfolds, either manually or electronically, over the fluid heating system may be provided to conceal the reflective surface of the outer housings of the fluid heating system. Also, the water reservoir may comprise bottles arranged in a different fashion. For instance, the bottles may be placed in a triangular arrangement within the reservoir. It will be appreciated that by arranging the bottles in a triangular arrangement there will be layers of bottles wherein there are more bottles in one layer than other layers. In an operative condition the upper most layers will have more bottles than the lower most layers. Furthermore, the water reservoir may include another form of container/vessel, without departing from the spirit and scope of the invention. 

1. A fluid heating system, wherein the fluid is capable of being heated by means of solar energy, the fluid heating system including: an outer housing; an inner housing contained within the outer housing and including a semi rigid absorbent material core located within the inner housing to define a flow passage between said absorbent material core and the walls of the inner housing; the absorbent material core being suitable for absorbing solar energy transmitted through the outer and inner housings; and wherein the outer housing; inner housing; and the absorbent material core are arranged such that solar energy is transferred through the fluid in the flow passage before being absorbed by the absorbent material core.
 2. The fluid heating system according to claim 1, wherein the fluid is water.
 3. The fluid heating system according to claim 1, wherein the fluid is potable water.
 4. The fluid heating system according to claim 1, wherein the outer housing includes a reflective surface for collecting and focusing solar energy onto the absorbent material core.
 5. The fluid heating system according to claim 4, wherein the reflective surface is in the form of a tin foil shield.
 6. The fluid heating system according to claim 1, wherein the heating system includes an actuating means for facilitating thermostatic control of the heating system.
 7. The fluid heating system according to claim 6, wherein the actuating means includes a rotating means for rotating the outer housing from a first position wherein the reflective surface is exposed to solar energy to a second position wherein the reflective surface conceals the absorber material core from solar radiation.
 8. The fluid heating system according to claim 1, wherein the absorbent material core is a black, hollow, cylindrical core.
 9. The fluid heating system according to claim 1, wherein the absorbent material core is a black, plastic, hollow, cylindrical core.
 10. The fluid heating system according to claim 9, wherein the absorbent material core is in the form of rubber crumb.
 11. The fluid heating system according to claim 1, wherein the outer housing includes a transparent plastic tubular body having an inlet at one end thereof and an outlet at an opposite end of the outer housing.
 12. The fluid heating system according to claim 11, wherein the transparent plastic tubular body of the outer housing is constructed from a plurality of polyethylene terephthalate 2 liter bottles.
 13. The fluid heating system according to claim 11, wherein the transparent plastic tubular body of the outer housing is constructed from a plurality of polyethylene terephthalate 2 liter bottles, wherein each said polyethylene terephthalate 2 liter bottle includes a neck portion, a body portion and a base portion and wherein the neck and base portions of each said polyethylene terephthalate 2 liter bottle have been removed leaving only the body portion.
 14. The fluid heating system according to claim 1, wherein the outer housing includes an inlet and an outlet, the inner housing includes a transparent plastic body having an inlet and outlet, the plastic body being adapted to be contained within the outer housing such that the inlet and outlet of the inner housing are located within the inlet and outlet of the outer housing.
 15. The fluid heating system according to claim 14, wherein the transparent plastic body of the inner housing is constructed from a plurality of polyethylene terephthalate 500 ml bottles.
 16. The fluid heating system according to claim 15, wherein the polyethylene terephthalate 500 ml bottles are arranged to form a solar energy absorber array.
 17. The fluid heating system according to claim 13, wherein the body portions of the plurality of polyethylene terephthalate 2 liter bottles are arranged end-to-end to form the tubular body of the outer housing.
 18. The fluid heating system according to claim 17, wherein one polyethylene terephthalate 2 liter bottle from which only the base portion has been removed and one polyethylene terephthalate 2 liter bottle from which only the neck portion has been removed, are positioned at opposite ends of the tubular body of the outer housing to provide the inlet and outlet, respectively.
 19. The fluid heating system according to claim 15, wherein the plurality of polyethylene terephthalate 500 ml bottles are arranged bottleneck-to-end to form the inner housing.
 20. The fluid heating system according to claim 19, wherein the bottleneck-to-end arrangement of the polyethylene terephthalate 500 ml bottles allows for fluid communication through the inner housing.
 21. The fluid heating system according to claim 1, wherein the heating system includes a plurality of outer housings.
 22. The fluid heating system according to claim 21, wherein the plurality of outer housings is supported on a frame.
 23. The fluid heating system according to claim 1, wherein a water reservoir is mounted above the frame.
 24. The fluid heating system according to claim 23, wherein the water reservoir includes a cold water supply inlet located at a bottom end of the water reservoir in fluid communication with a hot water delivery outlet located at a top end of the water reservoir.
 25. The fluid heating system according to claim 24, wherein the water reservoir includes a main delivery water pipe connected at one end to the cold water supply inlet and to a first series of manifolds at its other end.
 26. The fluid heating system according to claim 25, wherein the first series of manifolds are connected to the inlets of at least one of the inner and outer housings and a second series of manifolds are connected to the outlets of at least one of the inner and outer housings.
 27. The fluid heating system according to claim 26, wherein the second series of manifolds are connected to a further water pipe that supplies water flowing through the flow passages of the inner housings to the water reservoir.
 28. The fluid heating system according to claim 24, wherein the water reservoir is covered with an insulating material to prevent heat escaping from the water reservoir so as to maintain high water temperatures for a prolonged period of time.
 29. The fluid heating system according to claim 1, wherein the heating system is controlled so as to heat the fluid to a maximum temperature in the range of 50-70° C. 